1. Field of the Invention
The present invention relates to rate adaptation in a radio frequency (RF) communication system and in particular to rate adaptation using error vector magnitude values for RF devices supporting spatial multiplexing multiple-input multiple-output communication.
2. Related Art
The purpose of rate adaptation is to maximize the throughput of a radio frequency (RF) communication system by choosing the best data rate for given channel conditions. Typically, rate adaptation is based on a received signal strength indication (RSSI) and an (SNR, rate) lookup table (i.e. a table in which selecting a signal-to-noise ratio (SNR) indicates a corresponding rate). The RSSI is an accurate measurement of signal quality for single stream transmissions. However, where spatial multiplexing multiple-input multiple-output (MIMO) communication is supported in the RF device (e.g. receiver, transmitter, and/or transceiver), the RSSI no longer accurately reflects the quality of a received data stream. Therefore, a need arises for an accurate rate adaptation technique for RF devices supporting spatial multiplexing MIMO communication.